A wide variety of different dog food formulations of the wet and dry type are commercially available, e.g., from grocery, pet specialty and veterinary sources. Typically, such dog food formulations are generic in that they are designed to be consumed by any breed. However, some dog food formulations are specialized at least to the extent that they are preferably consumed by dogs of different ages, e.g, puppy, adult and geriatric dog formulations are widely available. Typically, such formulations differ in their caloric, protein, and fat content. Also, dog food formulations adapted for obese dogs are prevalent in the industry. Such dog food formulations, as might be expected, typically have a lower caloric content and higher fiber content relative to other dog food formulations.
In fact, there are many excellent premium pet foods in the marketplace which address the nutritional needs of pets from different perspectives. A good example of pet food formulations that address nutritional needs based on specific age are the Nature's Recipe Original.RTM. products. These diets address specific nutrient needs during an individual life stage. These diet lines differ widely with respect to the true differences among life stages. Because of the wide differences in rate at which breeds mature and absolute life-span differences, determination of the appropriate time to switch diets can be quite difficult. Other products address different energy requirements among pets, some of which may have a genetic component. The Puppy/Performance/-Lactation, Maintenance and Senior/Pension Lamb Meal & Rice Formulations incorporate a range of dietary energy levels as wide as any in the industry.
An additional segment of the pet food market incorporates differences in ingredient usage or product form. These fill the needs of some pet owners for taste and variety. Nature's Recipe.RTM. diets are well-represented in this segment as well since diets are formulated using a single meat protein source, allowing for true ingredient diversity. Many other product lines are fairly similar in ingredient selection with only minor differences in formulations. Relative to product form, Nature's Recipe Original.RTM. includes a complementary line of dry and canned products. Additionally, within canned products they offer a choice of ground or formed (carved) products.
A final segment of the pet food market which has been recently introduced involves formulations for specific breeds and/or adult weight. The Nature's Recipe.RTM. Group Specific Formulas excel in this category as they consider differences in nutrient requirements and physical form (size and mouth configuration) among breeds.
Such formulations have been developed in part because canine breeds differ from each other both on the outside and the inside. These differences include some of the more obvious things, including size at maturity, mouth and body dimensions. They also differ with respect to how fast they reach their mature weight. Some breeds, such as the Miniature Dachshund, reach mature body weight at approximately eight months of age while the Newfoundland takes over two years. This makes a huge difference in the physiological maturity of the dam at breeding age.
Although not marked, differences do exist in the digestibility of nutrients among breeds. While no comprehensive research for all breeds have been done, some research conducted by the present inventors has suggested that Toy Fox Terriers had a lower digestibility coefficient for the same diet than for the Beagle or Brittany, and that daily energy requirements to maintain body weight are lower for Miniature Poodles and higher for German Shorthairs and Coonhounds than the other breeds at our kennel. The latter likely resulted from the activity level of these breeds as they were quite active. On the same note, some breeds, such as Labrador Retrievers, Basset Hounds, Beagles, Cocker Spaniels, and several in the Terrier group, appear to be predisposed to obesity.
Finally, the ingredient tolerance and nutrient metabolism differ among breeds. This may result in different "normal" blood measurements. Published research has documented that, at least during the reproductive cycle, the Brittany has inherently lower levels of some standard blood measurements than the Beagle or Labrador Retriever. Some of these differences result from efficiencies of various enzyme systems in the body while others are the result of actual genetic abnormalities which accumulate over generations of breeding.
There have been 350-400 genetic disorders identified in dogs, compared to approximately 3,200 in humans. These disorders have been identified in approximately seventy percent of the recognized breeds and the prevalence in all dogs is thought to be approximately twenty-five percent. These genetic difficulties include anatomical malformations, errors of metabolism and genetic predispositions to conditions including cancer, bleeding disorders, and drug reaction. Often times the problem is an enzyme deficiency or defect in a specific structural protein in the body. This, in turn, results in a deficiency of some compound required by the body, a build-up of a compound at unusually high levels, or adaptation of metabolic pathways in the body to compensate for the problem. In the latter situation, clinical signs may not be evidenced or may only manifest themselves at times of high nutrient need. Some genetic defects are lethal either to the developing fetus or early in life, while others are not life-threatening.
Many of these conditions are inherited recessively and do not show up until two dogs which are carriers are bred. Unfortunately, screening tests are not available for many conditions and breeders often find out about problems only after a stud dog has been bred to numerous females. A carrier with an excellent show record can, therefore, spread the gene rapidly. It has been estimated that a single stud dog could represent five to ten percent of the entire genetic make-up of some rare breeds. Inbreeding per se is not necessarily the cause of expression of genetic problems but does expose them more readily. All biological organisms accumulate mutations over time and those which have fatal consequences become self limiting. Moreover, genetic defects are not exclusive to purebreds. It has been estimated that mixed breed dogs have 102 known defects, which is greater than many purebred breeds with a high incidence such as Cairn Terriers (37) and Cocker Spaniels (52). The reason for this is that many breeds have common genetic defects.
As indicated above, many healthy humans have genetic defects which force them to consume special diets. Any person who drinks a diet cola will find the phrase "phenylketonurics: contains phenylalanine" because some people have an inability to metabolize this amino acid (protein building block) so they should try to limit consumption. Another well known condition is lactose intolerance (inability to digest and utilize milk sugar) present in humans, especially those of Asian, Southern European, or African decent. The lack of persistence of the ability to digest milk after weaning is carried as a recessive gene. This situation is easily handled by avoidance of milk or consumption of enzymes which assist this digestion. A minority of the population in unable to regulate cholesterol synthesis in response to dietary intake, but it seems to be a dietary consideration in all of us. Incidence of most of the chronic diseases which occur in the geriatric population, including degenerative joint disease, heart disease, liver disease and diabetes also likely have genetic components.
Thus, pets, similar to humans, exhibit significant genetic diversity which affects their overall health and nutritional requirements. Therefore, notwithstanding the many different types of pet food formulations, and more specifically dog food formulations commercially available, there still exists a prevalent need for improved formulations that take into account the significant genetic differences between different breeds.